1. Field of the Invention
The present invention relates to an inductor, more particularly, to an inductor for use in, for example, high-frequency circuits and other such apparatuses, and to a method for adjusting the inductance value of an inductor.
2. Description of the Related Art
Through the miniaturization of mobile communication devices such as portable telephone terminals, etc., the demands for size reductions of electronic components used in these mobile communication devices are great. As a result, the inductance value of related lamination type inductors has been adjusted such that the pattern width of all of the portions of one or more coil patterns out of the coil patterns of several layers is uniformly made wider or narrower.
Here, when the size of lamination type inductors is even more reduced and the pattern width becomes finer, as shown in FIG. 8A, a coil pattern 1 having several turns is often formed on the same layer. In such a case, if the pattern width of the coil pattern 1 is made wider with reference to the center of the pattern in order to adjust the inductance value, the size of the coil pattern 1 on the same layer increases and this becomes an obstacle to size reductions of the inductors.
Then, if the pattern width is made wider in the inner direction of the coil pattern 1 in order to prevent the size of the coil pattern 1 on the same layer from increasing, as shown in FIG. 8B, a coil pattern 2 having a smaller inner diameter will be produced. The inductor having such a coil pattern 2 exhibited bad Q characteristics.
Furthermore, in the direction of the short side where the inner diameter is small, it was difficult to obtain an area in which a via pad 1a (see FIG. 8A) for connection between layers is disposed as a portion of the coil pattern.
In order to solve the problems described above, preferred embodiments of the present invention provide a much smaller inductor in which the degradation of Q characteristics is prevented, and a method for adjusting the inductance value of such a novel inductor.
According to a preferred embodiment of the present invention, an inductor includes a substantially rectangular insulation substrate and at least one coil pattern made of photolithographic material disposed on the insulation substrate, the at least one coil defining a spiral on the surface of the insulation substrate, and, in the coil pattern of the inductor, the electrode width and interelectrode spacing of a portion of the pattern provided in the vicinity of at least one short side of the two short sides of the substantially rectangular insulation substrate and arranged so as to be substantially parallel to the short side is wider than the electrode width of the other portion of the pattern. For example, the electrode width and interelectrode spacing of the portion of the pattern provided in the vicinity of the long side of the insulation substrate is arranged so as to be substantially parallel to the long side.
Furthermore, in a method for adjusting the inductance value of an inductor including a substantially rectangular insulation substrate and at least one coil pattern that is formed via photolithography, which defines a spiral on the surface of the insulation substrate, the inductance value is adjusted by increasing or decreasing the electrode width and interelectrode spacing of a portion of the pattern provided in the vicinity of at least one short side of two short sides of the substantially rectangular insulation substrate so as to be substantially parallel to the short side. Or the inductance value is increased by decreasing the electrode width and interelectrode spacing of a portion of the pattern provided in the vicinity of at least one long side of the insulation substrate so as to be substantially parallel to the long side.
Here, the expression of a coil pattern defining a spiral on the surface of an insulation substrate includes not only a coil pattern formed on the upper surface of the insulation substrate, but also a coil pattern formed above the insulation substrate through an insulation layer, or other suitable configuration.
When constructed as described above, fine adjustment of the inductance value becomes possible in an electronic component of a limited size and the degradation of Q characteristics is prevented and minimized.
Other elements, features, characteristics and advantages of the present invention will become more apparent from the following detailed description of preferred embodiments thereof with reference to the attached drawings.